Oblique femoral tunnel placement can increase risks of short femoral tunnel and cross-pin protrusion in anterior cruciate ligament reconstruction.
ABSTRACT A more horizontal femoral tunnel has been emphasized for contemporary anterior cruciate ligament (ACL) reconstruction. However, lowering the femoral tunnel may result in a shorter tunnel. In addition, a more horizontally placed femoral tunnel may have inadequate bone stock at the posterior portion of the tunnel, which can lead to protrusion of the cross-pin (Rigidfix) system for femoral fixation.
A more horizontal femoral tunnel position, particularly via the anteromedial (AM) portal technique, will reduce femoral tunnel length, and a more horizontal femoral tunnel position and anterior-to-posterior pin insertion will increase the risk of Rigidfix pin protrusion.
Controlled laboratory study.
In 10 cadaveric knees, we measured maximum lengths of the femoral tunnels at the positions of 11:30, 10:30, and 9:30 o'clock using the transtibial technique and at the 10:30 and 9:30 o'clock using the AM portal technique. Then, for each femoral tunnel via the transtibial technique at 11:30, 10:30, and 9:30 o'clock positions, tests were performed for 3 directions of Rigidfix pin insertion using the lateral epicondyle as an anatomical landmark, namely, 15 degrees anterior to posterior (A-P), neutral, and 15 degrees posterior to anterior (P-A). It was then determined whether pins protruded from the posterior cortex.
The lengths of femoral tunnels produced using the transtibial technique became shorter as the femoral starting position became more horizontal (51.1 mm, 40.0 mm, and 34.2 mm on average at the 11:30, 10:30, and 9:30 o'clock position, respectively). Tunnels made using the AM portal technique were significantly shorter than those made using the transtibial technique: by 7.6 mm at the 10:30 o'clock and 4.5 mm at the 9:30 o'clock positions on average (P < .001). In addition, increasing obliquity increased the likelihood of Rigidfix pin protrusion, especially when pins were inserted in the A-P direction.
The current effort to lower the femoral tunnel position in ACL reconstruction can shorten the tunnel length and compromise the graft fixation at the femur using the Rigidfix system.
When an intended femoral tunnel position is more horizontal than the 10:30 o'clock position for ACL reconstruction, a surgeon needs to be cautious regarding a short femoral tunnel, particularly when using the AM portal technique, and possible protrusion of the cross-pin (Rigidfix) fixator.
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ABSTRACT: Purpose To evaluate the relation between the tunnel angle in the 3 orthogonal planes, especially the sagittal plane, which can be influenced by knee flexion during drilling, and the incidence of complications from the transportal technique using in vivo imaging data. Methods Fifty-one patients who underwent anatomic double-bundle anterior cruciate ligament reconstruction by the transportal technique were evaluated retrospectively. A 3-dimensional surface model was made using an axial computed tomography scan obtained after anterior cruciate ligament reconstruction. The tunnel length, posterior cortical damage, proximity between the outer orifice of the tunnel and lateral collateral ligament (LCL) origin, and medial femoral condyle cartilage damage were evaluated on a 3-dimensional computed tomography scan and 3-T magnetic resonance imaging. Correlations between those parameters and the tunnel angle in the coronal, axial, and sagittal planes were analyzed. Results A tunnel length of less than 30 mm developed in 4 cases (8%) in the anteromedial tunnel and in 1 case (2%) in the posterolateral (PL) tunnel. Posterior cortical damage developed in 12 cases (23%). A distance from the outer orifice of the tunnel to the LCL origin of less than 3 mm occurred in 18 cases (35.2%) in the PL tunnel. Medial femoral condyle cartilage damage was detected in 3 cases (6%). A positive correlation was observed between the sagittal angle and anteromedial tunnel length (P = .002, r = 0.547). The sagittal angle in the group with posterior cortical damage was lower than that in the group with no posterior cortical damage (P = .002). A negative correlation was observed between the distance from the outer orifice of the PL tunnel to the LCL origin and the sagittal angle (P = .002, r = −0.55). Conclusions Drilling at a higher angle in the sagittal plane decreased the incidence of posterior cortical damage and a short anteromedial tunnel. However, drilling at a higher angle shortened the distance to the LCL origin for the PL tunnel. Level of Evidence Level IV, therapeutic case series.Arthroscopy The Journal of Arthroscopic and Related Surgery 10/2014; 31(2). DOI:10.1016/j.arthro.2014.08.018 · 3.19 Impact Factor
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ABSTRACT: The success of ACL reconstruction is predicated on a variety of factors. Tunnel placement plays one of the most significant roles in achieving knee kinematics and function. The purposes of this study were to compare femoral tunnel position, angle, length and posterior wall blow-out after ACL reconstruction with hamstring tendons autograft through either a farmedial portal or an anteromedial portal technique. We evaluated 36 patients who underwent ACL reconstruction between January 2014 and July 2014 in our institute, in a prospective, randomised cohort study. All the surgical procedures were performed by a sports fellowship-trained orthopaedic surgeon with experience in both portal reaming. The operated knees were evaluated with 0.5 mm fine CT scans of 3-D CT between days 3 and 5 postoperatively. According to the 3-D CT measurements, the mean femoral tunnel length was significantly longer (p < 0.05) in the FAM group compared with the AM group. The femoral bone tunnel length averaged 34.2 ± 3.6 mm versus 36.6 ± 3.0 mm (p = 0.042) in AM and the FAM groups, respectively. The femoral tunnel position, as evaluated with use of the quadrant method, was more anterior in the FAM transportal technique group, and the difference between the two groups was significant (p < 0.05). FAM tranportal drilling of the femoral tunnel creates longer and anterior femoral tunnels with regard to the AM portal drilling techniques. Additional studies with clinical outcomes are required for the clinical relevance of these techniques and to show which one is superior. Level I, prospective randomised comparative cohort study.Archives of Orthopaedic and Trauma Surgery 02/2015; 135(4). DOI:10.1007/s00402-015-2176-z · 1.36 Impact Factor
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ABSTRACT: Objetivo Avaliar uma série de pacientes submetidos à cirurgia de reconstrução do ligamento cruzado anterior com tendões flexores pela técnica transportal anteromedial com o uso de Rigidfix para fixação femoral e analisar o posicionamento dos pinos por meio de tomografia. Métodos Foram incluídos no estudo 32 pacientes. A avaliação clínica foi feita com os escores de Lysholm, IKDC subjetivo e Rolimeter. Todos foram submetidos a tomografia computadorizada com reconstrução em 3D para avaliação do ponto de entrada e do posicionamento dos pinos do Rigidfix em relação à cartilagem articular do côndilo lateral do fêmur. Resultados A média do escore de Lysholm obtido foi de 87,81 e do IKDC subjetivo, de 83,72. Dos 32 pacientes avaliados, 43% retornaram a atividades consideradas muito vigorosas, 9% a vigorosas, 37,5% a moderadas e 12,5% a leves. Em 16 pacientes (50%), o ponto de entrada do pino distal do Rigidfix foi localizado fora da cartilagem (extracartilagem), em sete (21,87%) o pino distal lesou a cartilagem articular (intracartilagem) e em nove (28,12%) ficou na borda da cartilagem articular do côndilo lateral do fêmur. Conclusão Os pacientes submetidos à reconstrução do LCA com o sistema Rigidfix pela técnica transportal anteromedial apresentaram um resultado clínico satisfatório no tempo de seguimento avaliado. Entretanto, o risco de lesão da cartilagem articular pelo pino distal do Rigidfix deve ser considerado quando a técnica via portal anteromedial é usada. Outros estudos com maior número de pacientes e com um tempo de seguimento mais longo devem ser feitos para melhor avaliação.11/2014; 49(6). DOI:10.1016/j.rboe.2014.10.004